Boku to Kyouju no Nijuunen

A heart-warming story about a cat and its human. Born in the same year, the cat named “Professor” had been by its owner’s side for 20 years. Always together through dark times and first loves, the time they’ve spent is an irreplaceable treasure. Spanning from their youth to their last farewell, this is a story showing how the most ordinary days are the most important, beloved times.

(Source: Manga Planet)